1. Field of the Invention
The present invention concerns a medical examination apparatus for acquisition of slice images of an examination subject, in particular a magnetic resonance apparatus, of the type having a control device that controls the image acquisition procedure, with at least one associated monitor on which can be displayed graphic elements serving for setting the image acquisition parameters, the graphic elements being positionable by the user via an input unit with regard to an image simultaneously displayed on the monitor, the control device controlling the image acquisition operation dependent on the position and type of the graphic elements.
2. Description of the Prior Art
Magnetic resonance or computed tomography systems are used primarily for acquisition of slice images of an examination subject. In order to be able to exactly set the image acquisition parameters, previously acquired overview slice images that show the examination subject are displayed to the physician or to the technician on one or more monitors. One or more graphic elements then are superimposed in this image. These graphic elements may be of different types and allow the image acquisition parameters to be defined and individually adjusted by the physician. The graphic elements, for example, can more specifically define the site of the image acquisition, thus the examination site, for example 2D and 3D slice elements that determine the position and orientation of the slice to be acquired, or volume elements or spatial grids (for example for CSI spectroscopy (CSI=Chemical Shift Imaging)). In addition, the graphic elements can be positioned, so that, for example, specific regions visible in the displayed overview images can be virtually masked out; these regions then are saturated in the imaging procedure, which can be defined by corresponding saturation elements.
Depending on the examination method or on the examination subject, it may be necessary for a particular measurement or a measurement task (measurement protocol) to position a number of graphic elements, these being primarily aligned in three-dimensional patient space to the anatomy of the patient (defined, for example, by three previously-acquired overview images that are orthogonal to one another). These graphic elements simultaneously must be aligned among one another in a fixed spatial relationship (for example parallel to each other with predetermined separation, perpendicular to each other with a common center point, at a predetermined angular ratio to each other, etc.). The graphic elements are to be positioned separately by the physician, i.e. the physician designs the measurement task or the measurement protocol virtually step-by-step by positioning the individual graphic elements. If, for example, after concluding positioning the physician determines the selected arrangement is to be changed, this causes every graphic element to be separately repositioned, which is very laborious and time-consuming because many individual manual steps have be re-executed. Even small variations involve a series of corrections to objects to be aligned relative to one another, but it is essential that this be done to achieve a meaningful image acquisition.